At his death in 1882, Emerson left behind a trove of unpublished material extraordinary for its quantity and depth-hundreds upon thousands of pages of journals, letters, notebooks, and lectures that dwarf his nine books in volume and scope but were never seen during his lifetime. His most important manuscripts have gradually filtered through to the public over the course of the last hundred and twenty-five years, save one: the final product of what he himself considered to be the "chief task of his life." Here for the first time in print are the last lectures of Emerson's career, a cycle of...